Corrugated boxes are typically produced in large machines which have several sections, each of which performs one or more steps in the mass production of the boxes. These sections often include an inking section, a gluing section, a folding section, a delivery section and a stacking section.
In operation, corrugated board is fed into the inking section of the corrugated box machine. Here the board is cut, printed and scored for folding. From the inking section the board travels into the gluing section where a bead of glue is applied along one edge of the board. The board then travels into the folding section where long rotating belts convey the board and cause the outer edges of the board to be folded inwardly along the scorelines. As the edges fold over, the glued edge is folded onto the unglued edge to form a seal. Once the board is glued, folded and sealed, it then passes into the delivery section which facilitates the transfer of the finished corrugated box from the folding section into the separate stacking section.
A common problem involved with the folding process is that the leading and trailing edges of the corrugated board become skewed. It is therefore an object of this invenion to provide a corrugated board conveying system which will produce a properly aligned corrugated box.
Another problem with present corrugated box machines involves the belts used for conveying the board material through the gluing and folding sections of the machine. As the belts become worn, they begin to stretch and slip on the rollers and drive pulleys. This is particularly true with the lower main drive belts. It is therefore an object of this invention to provide a corrugated board conveying system which will lessen the slippage of the belts about their respective rollers and drive pulleys.
Once the corrugated box emerges from the folding section, it passes into the delivery section. The delivery section of prior art machines consist of a pair of upper and lower kidney belt assemblies which are used to keep smaller boxes in alignment as they cross the void between the folding and stacking sections of the machine.
The reason for the void between the two sections is that the entrance to the stacking section contains two vertical spiral gears which contact the outer edges of the finished corrugated box and gradually lift the box up and out of the way of the next box exiting the folding section. If the spiral gear is too close to the folding section, longer boxes become bent because the leading edge of the box reaches the top of the spiral before the trailing edge is freed from the folding section. Consequently, upper and lower kidney belt assemblies are used to increase the distance between the two sections.
The upper kidney belt in the prior art machinery is pivotally mounted. Thus when small corrugated boxes are being run, the upper kidney belt can be positioned atop the lower kidney belt to guide the smaller boxes as they pass from the folding section into the stacking section. When larger boxes are being run, the upper kidney belt assembly is pivoted up and out of the way to prevent bending of the larger boxes.
The kidney belts are driven by long drive shafts. As a result, when an old or damaged belt has to be replaced, the entire drive shaft has to be pulled through the machine to replace the belt. This results in costly losses in money and operation time while repairs are being made. It is therefore an object of this invention to provide an improved box conveying system which alleviates the need for such kidney belt assemblies.
Finally, when very wide boxes are being run, they tend to sag under their own weight. This can cause jamming and also loosen the glue seal between the two folded edges of the box. It is therefore an object of this invention to provide a box conveying system with an improved and simplified box support means.
Other objects and advantages of the invention will become apparent as the invention is described hereinafter in detail and with reference to the accompanying drawings.